On Tuesday, it was the spiritualists, Wednesday the Liberal Democrats and on Thursday it was the turn of the republicans to use the Friends Meeting Room in Taunton.

Outraged by the revelation that the Queen had questioned the home secretary in 2003 on why the Muslim cleric Abu Hamza remained free, eight republicans from Taunton and its surrounding villages gathered to hear Graham Smith, the chief executive of campaign group Republic, outline his plans for the overthrow of the monarchy.

It might seem that the last two years of royal pageantry mark a low point for British republicans, but paradoxically the organisation has grown from 9,000 supporters on the eve of the announcement of the royal wedding to 26,000 today. Blanket coverage of the wedding of the Duke and Duchess of Cambridge and the Queen's jubilee produced emotions from excitement to warm indifference to the monarchy to opposition.

"Most people put up with them unless it's rammed down their throat. The wedding has been brilliant for us. The royal family has a higher profile and that helps us," said Smith.

Republicans view the uncertainty surrounding an ageing monarch as a great opportunity to raise the profile of their cause. "Let's say the Queen lives for another 20 years – that's a big opportunity there. The older she gets the more debate there will be about what happens next. When will the succession take place? Do people want Charles or William? It's all a bit morbid and weird and it will heighten the absurdity of it all," said Smith. "The succession will be huge. There were no questions asked in 1952. This time people will ask why is this person being handed this job without being voted for."

The issue is not yet popular with the young. At the meeting house, seven of the supporters are in their 50s or older, at least two are teachers and one is an engineer at the AgustaWestland helicopter factory in Yeovil.

The Abu Hamza issue, which emerged last week when BBC correspondent Frank Gardner said that the Queen had told him of her concern at the preacher's continued liberty in 2003 and her inquiries to the home secretary on the matter, is a topic of conversation as is the BBC's subsequent apology for breaking the Queen's confidence.

"This illustrates the myth that the Queen is above politics and the cosy relationship the BBC has with the palace. If she is asking questions of the home secretary, it's not difficult to imagine that she is asking questions of the chancellor the exchequer, like why isn't the deficit going down, which would be explosive," said Smith.

"A lot of the monarchy's popularity endures because it is shrouded in secrecy. If people knew what was going on, there would be a lot more questions."

During the meeting, one woman describes the royals as "rather sinister wallpaper", another likens their propensity to award themselves medals and military promotions to North Korea. The coronation of Prince Charles is also seen as hopeful by republicans because of his limited popularity – only 39% of Britons want him to succeed – and a perception that he would want to play a more active role as monarch than his mother. "If we can stop him getting there, that would be better," said Smith.

Republic was established in 1983. Smith is the only full-time officer, working with two part-timers. They have no office and receive funds from subscriptions and donations.

Last week Smith travelled from Bristol to Taunton, which was partially destroyed by royalists in the civil war during the sieges of 1644 and 1645, to leaflet shoppers and meet local activists. Then he debated at the University of Exeter and went to Truro to launch a campaign for the abolition of Prince Charles's lucrative Duchy of Cornwall.

In Taunton, there are few signs of Jacobinism, although Kate Forsyth from Chard described how she suggested that a novel idea for the future might be the demolition of Buckingham Palace and the construction of affordable housing in its place. "I have always hated inequality. We need to have a culture where you earn respect rather than receive automatic deference," she said.

Smith cannot think of a country that has moved from monarchy to a republic without war or revolution but believes peaceful change in Britain is possible.

Republic champions an elected head of state like the Republic of Ireland. "Robinson, McAleese and Higgins [the last three Irish presidents] are all quite inspiring," said Smith.

He does not believe that the Queen's age puts her beyond criticism. "I think it's rather patronising to think she's old so that we shouldn't criticise her. I take the view that she's an adult, she's old enough to look after herself and she is in a job, in a public office and she should be held to account for that," he said.

The sparse numbers in the Friends Meeting House do not suggest an incipient revolution, peaceful or otherwise, but one republican offers the group an encouraging story. "I was at a Liberal Democrat meeting a few years ago and there was the same number of people. And look where we are now."